Byzantine church, now a mosque
Hagia Sophia, Trabzon
A 13th-century Byzantine church of the Empire of Trebizond, a museum from 1964 and a mosque again since 2013. It is a different building from Istanbul's Hagia Sophia. The Doğu Karadeniz Kültür Envanteri Projesi states free admission; as a working mosque, visiting follows prayer times. It has its own place page.